U.S. patent number 4,608,017 [Application Number 06/610,687] was granted by the patent office on 1986-08-26 for endodontic irrigating instrument.
This patent grant is currently assigned to Micron Co., Ltd.. Invention is credited to Tsuyoshi Sadohara.
United States Patent |
4,608,017 |
Sadohara |
August 26, 1986 |
Endodontic irrigating instrument
Abstract
An endodontic irrigating instrument comprises a handpiece having
an internal liquid passage therethrough extending from a liquid
inlet formed in the proximal end of the handpiece to a liquid
ejection nozzle provided at the distal end. The handpiece
incorporates a suction or vacuum pump of the airjet or ejector type
which comprises an air nozzle connected by a passage with an air
inlet formed also in the proximal end of the handpiece. The vacuum
chamber of the suction pump is connected by a separate internal
passage in the handpiece with an aspiration needle provided
adjacent to the liquid ejection nozzle. The proximal end of the
handpiece is designed to be fitted with a coupling joint attached
to a multiple-channel flexible hose which is conventionally used to
supply compressed air and pressurized water from a dental unit to
conventional air-driven dental turbine tools. Thus, the endodontic
irrigating instrument can be used interchangeably with existing
turbine tools.
Inventors: |
Sadohara; Tsuyoshi (Yokohama,
JP) |
Assignee: |
Micron Co., Ltd. (Tokyo,
JP)
|
Family
ID: |
26430277 |
Appl.
No.: |
06/610,687 |
Filed: |
May 16, 1984 |
Foreign Application Priority Data
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May 20, 1983 [JP] |
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58-88951 |
Aug 1, 1983 [JP] |
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58-140932 |
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Current U.S.
Class: |
433/81 |
Current CPC
Class: |
A61C
5/40 (20170201); A61C 17/0208 (20130101) |
Current International
Class: |
A61C
17/02 (20060101); A61C 17/00 (20060101); A61C
5/02 (20060101); A61C 005/02 () |
Field of
Search: |
;433/81,91,118 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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673696 |
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Mar 1939 |
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DE2 |
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3026929 |
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Jul 1980 |
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DE |
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1334134 |
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Sep 1962 |
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FR |
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2234884 |
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Jun 1974 |
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FR |
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256175 |
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Feb 1949 |
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CH |
|
Other References
Primary Examiner: Peshock; Robert
Attorney, Agent or Firm: Merchant, Gould, Smith, Edell,
Welter & Schmidt
Claims
I claim:
1. An endodontic irrigating instrument for irrigating a root canal
of a tooth, which comprises:
a handpiece having a proximal end and a distal end, said proximal
end having an inlet for a compressed air and an inlet for an
irrigating liquid under pressure and being so formed as to be
coupled with a multiple-channel hose extending from a dental
unit;
a suction pump of the airjet type incorporated with said handpiece
at the region adjacent said proximal end thereof, said suction pump
having an air nozzle and and exhaust port;
air passage means for supplying a flow of compressed air from said
air inlet to said nozzle to create a zone of partial vacuum in said
pump;
a hollow aspiration needle mounted at an end thereof to said distal
end of the handpiece, the other end thereof having an outer
diameter substantially smaller than the inner diameter of the root
canal to be irrigated;
suction passage means for connecting said zone of partial vacuum
with said aspiration needle to suck the irrigating liquid therein
and to discharge it toward said exhaust port;
a liquid ejection nozzle provided at said distal end of the
handpiece adjacent said aspiration needle for supplying the
irrigating liquid along said aspiration needle;
liquid passage means for supplying the irrigating liquid under
pressure from said liquid inlet to said ejection nozzle; and
valve means for directing the compressed air to flow in the reverse
direction through said suction passage toward said aspiration
needle to permit backwashing of the aspiration needle.
2. An endodontic irrigating instrument as defined in claim 1,
wherein said valve means comprises: a valve cylinder aligned with
said exhaust port of said suction pump, said valve cylinder having
an inlet port communicating with said air passage; a hollow movable
spool forming said air nozzle of said suction pump and defining a
circumferential annular space communicating with said inlet port in
said valve cylinder, said movable spool having an inlet port
communicating said annular space with the internal passage of said
air nozzle, said movable spool being received slidably within said
valve cylinder from a first position in which said air nozzle is
away from said exhaust port to a second position in which said
annular space of said movable spool is in open communication with
said zone of partial vacuum in said pump and in which said air
nozzle closes said exhaust port, said movable spool being normally
biased toward said first position; and means including a push rod
for opening and closing said inlet port of said movable spool.
3. An endodontic irrigating instrument as defined in claim 2,
wherein said air nozzle and said exhaust port extend substantially
parallel to the longitudinal general axis of the handpiece in the
direction from said distal end to said proximal end.
4. An endodontic irrigating instrument as defined in claim 1,
wherein said aspiration needle is mounted to said distal end of the
handpiece through a suction tube.
5. An endodontic irrigating instrument as defined in claim 4,
wherein said aspiration needle is made from a flexible
material.
6. An endodontic irrigating instrument as defined in claim 5,
wherein said aspiration needle is made from a transparent
material.
7. An endodontic irrigating instrument as defined in claim 6,
wherein said material is polypropylene.
8. An endodontic irrigating instrument as defined in claim 6,
wherein said material is polyethylene.
9. An endodontic irrigating instrument as defined in claim 4,
wherein said suction tube extends at an angle with respect to the
longitudinal general axis of the handpiece.
10. An endodontic irrigating instrument as defined in claim 1,
wherein said handpiece comprises a first section including said
proximal end and a second section including said distal end, said
second section being mounted to said first section for swivelling
movement with respect to said first section about the longitudinal
general axis of the handpiece so that said aspiration needle is
turned at any desired rotational angle with respect to said first
section.
11. An endodontic irrigating instrument as defined in claim 1,
further comprising means for regulating the flow rate of the
irrigating liquid flowing through said liquid passage.
12. An endodontic irrigating instrument for irrigating a root canal
of a tooth, which comprises:
a handpiece having a proximal end and a distal end, said proximal
end having an inlet for a compressed air and an inlet for an
irrigating liquid under pressure and being so formed as to be
coupled with a multiple-channel hose extending from a dental
unit;
a suction pump of the airjet type incorporated with said handpiece
at the region adjacent said proximal end thereof, said suction pump
having an air nozzle and and exhaust port;
air passage means for supplying a flow of compressed air from said
air inlet to said nozzle to create a zone of partial vacuum in said
pump;
a hollow aspiration needle mounted at an end thereof to said distal
end of the handpiece, the other end thereof having an outer
diameter substantially smaller than the inner diameter of the root
canal to be irrigated;
suction passage means for connecting said zone of partial vacuum
with said aspiration needle to suck the irrigating liquid therein
and to discharge it toward said exhaust port;
a liquid ejection nozzle provided at said distal end of the
handpiece adjacent said aspiration needle for supplying the
irrigating liquid along said aspiration needle;
liquid passage means for supplying the irrigating liquid under
pressure from said liquid inlet to said ejection nozzle; and
valve means for directing the compressed air to flow in the reverse
direction through said suction passage toward said aspiration
needle to permit backwashing of the aspiration needle, said valve
meaning including a valve cylinder aligned with said exhaust port
of said suction pump, said valve cylinder having an inlet port
communicating with said air passage; a hollow movable spool forming
said air nozzle of said suction pump and defining a circumferential
annular space communicating with said inlet port in said valve
cylinder, said movable spool having an inlet port communicating
said annular space with the internal passage of said air nozzle,
said movable spool being received slidably within said valve
cylinder from a first position in which said air nozzle is away
from said exhaust port to a second position in which annular space
of said movable spool is in open communication with said zone of
partial vacuum in said pump and in which said air nozzle closes
said exhaust port, said movable spool being normally biased toward
said first position; and means including a push rod for opening and
closing said inlet port of said movable spool.
Description
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to an instrument for use in dental
surgery and, more particularly, to an endodontic instrument for
irrigating the root canal of a tooth with an irrigating liquid.
(2) Description of the Prior Art
In root canal treatment such as pulpectomy and root canal apical
seat preparation, it is essential that the cuttings and dental pulp
tissue fragments resulting from reaming by reamer files be
completely removed from the root canal, by washing, and the inside
of the root canal be perfectly disinfected and dried prior to
filling. Also, an open end root canal containing food stuff
residuals must be irrigated before each treatment.
Of the known endodontic irrigating instruments, there is a minium
syringe by which irrigating solutions such as a hydrogen peroxide
solution and sodium hypochlorite solution are alternately injected
into the root canal. One of the disadvantages of the minium syringe
is that the volumetric capacity is limited, and the irrigating
solutions must be often replenished. Another disadvantage is that
if the irrigating needle of the minium syringe is inserted too
deeply into the root canal or the pressure of the irrigating
solutions is augmented to enhance the irrigating effect, there is a
danger that the irrigating solution will flow through the apical
dental foramen into the periapical area, thereby breaking the
periapical tissue or, in some cases, causing the formation of
pneumatosis. A further disadvantage of the minium syringe is that a
suction tube of a saliva remover must be inserted into or hang from
the mouth to extract the used irrigating solutions. This hinders
the work of the dentist and gives discomfort or pain to the
patient.
Another irrigating instrument known in the art is the so-called
"triple syringe". This instrument includes a nozzle connected by
flexible hose with a source of compressed air and a source of
pressurized water or solution provided in the dental unit, and is
adapted to selectively eject either an airjet, a waterjet, or a
mixture thereof. The triple syringe is not considered suitable for
endodontic irrigation of a narrow root canal because the nozzle of
the syringe is considerably larger in size than the diameter of the
tooth cavity opening. This entails positioning the nozzle outside
the tooth cavity and blowing the jet of air, water or mist from
above the tooth cavity opening, making it practically impossible to
produce a path within the root canal for the incoming jet and a
counter-current path for the outgoing fluid, thus limiting the
irrigating effect of the triple syringe. Another drawback of this
instrument is that it is impossible to dispose of an air bubble
trapped at the root canal apex region, to rinse that region.
Moreover, as for the minium syringe, a saliva remover is required
to remove the liquid after use from the patient mouth.
There is also known in the art an endodontic irrigating equipment
which comprises a handpiece connected through a flexible
multiple-channel hose with a remote main unit in which a vacuum
pump is provided. The head of the handpiece comprises a suction or
aspiration tube projecting therefrom and connected with the vacuum
pump via a suction conduit in the handpiece and the flexible hose.
A hollow irrigating needle is mounted to the handpiece head at the
center of the suction tube, to project beyond the suction tube.
Thus, an annular space is formed between the suction tube and the
needle, to which space a partial vacuum is applied from the vacuum
pump. The irrigating needle is connected through one or more liquid
conduits in the handpiece and through passages in the hose with one
or more reservoirs for irrigating solutions. An annular sealing
rubber is attached to the end of or around the suction tube. In
use, the irrigating needle is inserted into the root canal with the
sealing rubber being tightly urged against the tooth, to
hermetically seal the annular gap between the tooth cavity and the
suction tube. Then the vacuum pump is operated to apply a partial
vacuum within the tooth cavity so that the irrigating solution is
injected through the irrigating needle into the bottom of the root
canal under the action of the vacuum. The issued irrigating
solution flows from the bottom to the top of the root canal and
then into the pulp chamber and, by so doing, washes away the
cuttings and rinses the internal cavity of the tooth. The used
solution is sucked into the suction tube and is evacuated to a
waste container provided in the main unit.
This irrigating equipment enjoys a certain advantage over the
above-mentioned irrigating instruments in that the irrigating
needle can be inserted deep in the root canal and that the used
irrigating solution is discharged simultaneously with the rinsing
operation.
However, this equipment requires a main unit provided with a vacuum
pump and is used exclusively for the sole purpose of irrigation.
This increases the cost of the equipment and imposes a financial
burden on the dentist. Further, it is often difficult to perfectly
seal the gap between the tooth and the suction tube with the
sealing rubber. In the event of improper sealing, the tooth cavity
will not be subjected to vacuum strong enough to suck the
irrigating liquid into the cavity and to also generate the jet of
irrigating solution required for washing. A further disadvantage of
this irrigating equipment is that, as the opening of the tooth
cavity is sealed by the sealing rubber, visual inspection by the
dentist of the root canal is prohibited. Still further, it is
impossible to move the irrigating needle along the root canal in an
attempt to wash the various region of the canal, because the head
of the handpiece is fixed by the sealing rubber. Thus, if the
bottom of the root canal near the root apex is to be rinsed, the
depth of the root canal must be measured beforehand by X-ray
photographs and the needle must be cut to a desired length.
Similarly, where upper regions of the root canal are to be
irrigated, a number of needles having various lengths must be
provided and successively exchanged. The use of sealing rubber
causes another inconvenience. That is, as the outlet of the
irrigating needle is positioned at a fixed location of the root
canal and the solution is supplied only at that location, other
areas of the root canal must be washed by the back flow of the
solution. This resulted in a poor irrigating performance. A further
drawback of this equipment is that it is incapable of removing a
liquid droplet trapped by the capillary or adhesive action at the
region of the root canal apex or apical foramen, because the
suction takes place at the upper region of the tooth cavity where
it is sealed.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an
endodontic irrigating instrument which functions without recourse
to a separate vacuum pump containing unit and which is operated by
a drive source of an existing dental unit which is standard
equipment in almost all dental clinics.
Another object is to provide an endodontic irrigating instrument
which is capable of being connected by a single action with an
existing multiple-channel hose extending from the dental unit and
used for coupling the turbine-driven dental instruments such as
drilling tools, and which is readily interchangeable with such
turbine-driven instruments when necessary.
A further object is to provide an endodontic irrigating instrument
which may be controlled by an existing foot switch of the dental
unit.
Still another object is to provide an endodontic irrigating
instrument which is capable of discharging used irrigating solution
simultaneously with the rinsing operation and which does not
require an additional saliva remover.
A still further object is to provide an endodontic irrigating
instrument which is capable of rinsing any desired location of the
tooth cavity including the root canals and pulp chamber,
particularly the apex region of the root canal, where an air bubble
or liquid droplet tends to be trapped.
A further object is to provide an endodontic irrigating instrument
which permits quick and perfect removal of used irrigating
solutions from any location in the root canal and which is capable
of drying the root canal to a degree sufficient for subsequent
filling operation.
A further object is to provide an endodontic irrigating instrument
which can obviate the danger of pneumatosis and fracture of the
apical dental foramen that would otherwise be caused due to the
high-pressure and high-velocity jet of irrigating solutions.
A further object is to provide an endodontic irrigating instrument
which permits visual inspection of the root canal during
irrigation.
A yet further object is to provide an endodontic irrigating
instrument having an irrigating needle which is capable of being
oriented at any desired angular position at the option of the
dentist, to facilitate irrigation of any tooth at any position.
A still further object is to provide an endodontic irrigating
instrument which is capable of controlling the flow rate of
irrigating solutions.
Another object is to provide an endodontic irrigating instrument
which is capable of backwashing the aspiration needle and suction
passages when they are clogged by cuttings and the like.
An endodontic irrigating instrument according to the present
invention comprises a handpiece having proximal and distal ends and
an intermediate portion therebetween. An air inlet and a liquid
inlet are provided at the proximal end of the handpiece to receive
compressed air and an irrigating solution, respectively. The
handpiece proximal end is adapted to be coupled with a
multiple-channel hose extending from a dental unit. The
intermediate portion is designed to be gripped by the operator. The
distal end, forming the head of the handpiece, is provided with a
suction tube to which is detachably mounted a hollow aspiration
needle. A liquid ejection nozzle is provided at the distal end of
the handpiece, adjacent to the suction tube, to supply the
irrigating liquid under pressure along the aspiration needle.
The handpiece incorporates an airjet-type suction pump at the
region adjacent to the proximal end of the handpiece. The pump is
connected by an air passage with the air inlet and is energized by
the compressed air to produce a zone of partial vacuum, which is
transmitted through a suction passage in the handpiece and the
suction tube to the aspiration needle.
The irrigating liquid under pressure, such as water and irrigating
solution, is fed from the liquid inlet via a liquid passage in the
handpiece to the ejection nozzle, flows therefrom at a controlled
flow rate along and around the aspiration needle and is injected
into to root canal to be irrigated.
Preferably, the aspiration needle is formed from a flexible,
transparent material and is tapered toward its free end which has
an outer diameter substantially smaller than the inner diameter of
the root canal. The irrigating liquid after rinsing the internal
wall of the root canal is sucked under the action of the vacuum
into the aspiration needle and is discharged toward an exhaust port
of the suction pump together with the used drive air.
This invention also features a suction tube for mounting the
aspiration needle positioned at an angle with respect to the
longitudinal general axis of the handpiece, to facilitate the
dentist's work.
According to another feature of the invention, the handpiece
comprises a first section including the proximal end and a second
section including the distal end, the second section being mounted
on the first section for rotation about the longitudinal general
axis of the handpiece to enable the operator to direct the
aspiration needle at any desired angular position.
Preferably, a flow control valve is provided in the liquid supply
passage to regulate the flow rate of the irrigating liquid ejected
from the nozzle.
The suction pump may be positioned transversely to the handpiece so
that the exhaust port of the pump extends at a right angle to the
handpiece.
In an alternative embodiment, the suction pump may be disposed
parallel to the longitudinal general axis of the handpiece so that
the exhaust port is directed rearward. In use, the exhaust port of
the suction pump may be coupled to a flexible conduit leading to a
suitable waste disposal installation, such as a spitoon provided in
the dental unit.
In another embodiment, the endodontic irrigating instrument further
comprises a valve mechanism for closing the exhaust port of the
airjet pump and directing the compressed air to flow through the
suction passage in the handpiece toward the aspiration needle,
thereby permitting backwashing of the aspiration needle and suction
tube.
These and other features of the present invention, as well as the
advantages thereof, will become apparent when reading the following
description in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal vertical cross-sectional view of an
endodontic irrigating instrument according to the present
invention;
FIG. 2 is a rear end view of the instrument shown in FIG. 1;
FIG. 3 is a partial horizontal cross-sectional view of the
instrument shown in FIG. 1, coupled with a coupling joint;
FIG. 4 is a schematic representation showing irrigation of a root
canal using the instrument according to the present invention;
FIG. 5 is a schematic representation showing the irrigation liquid
sucked into the aspiration needle;
FIG. 6 is a longitudinal vertical cross-sectional view of another
embodiment of the present invention;
FIG. 7 is a longitudinal vertical cross-sectional view of a further
embodiment of the present invention; and,
FIGS. 8 and 9 are enlarged cross-sectional views showing the airjet
suction pump with a built-in backwash control valve of the
embodiment of FIG. 7, with FIG. 8 illustrating the pump in the
operating condition and the valve in the inoperative position, and
FIG. 9 illustrating the pump in the inoperative condition and the
valve in the operating position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, FIGS. 1 through 3 illustrate a first
embodiment of the present invention. The endodontic irrigating
instrument, generally designated 10, comprises a handpiece 12 which
extends from its proximal end 14 to its distal end 16. As seen in
FIG. 1, the hand piece 12 is designed to be gripped by an operator
along the intermediate portion between the proximal end 14 and
distal end 16. In the illustrated embodiment, the handpiece 12 is
divided into two sections, i.e., a first section 18 and a second
section 20, which are coupled together to permit relative rotation
by a swivel joint mechanism 22, described later. The second section
20, in turn, includes a tubular main piece 24 extending along the
longitudinal general axis of the handpiece 12, a tubular
intermediate piece 26 firmly joined to the main piece 24 by a
threading engagement at 28, and a head piece 30 press-fitted to the
intermediate piece 26. As shown, the intermediate piece 26 is
slanted to raise the head piece 30 at an angle.
The first section 18 is generally cylindrical and the end 14 of the
section is adapted to be coupled with a coupling joint 32,
described later and shown by dotted line in FIG. 3. For this
purpose, the end 14 is recessed stepwise and an annular groove 34
is formed. Also, the first section 18 has a stepped bore for
receiving a core 36 of the coupling joint 32, the stepped bore
serving also to form an air inlet 38 and a liquid inlet 40.
The first section 18 of the handpiece 12 is provided with a suction
or vacuum pump 42 of the type known as an airjet or ejector pump.
The suction pump 42 comprises an air nozzle 44 press-fitted within
a radially extending stepped bore in the section 18, and a venturi
tube 46 screwed partly into the radial bore. The venturi tube 46
defines therein a vacuum or suction chamber 48, a mixing chamber
50, and an exhaust port 52, which is formed in a diffuser portion
of the venturi tube 46. The air nozzle 44 communicates with the air
inlet 38 through an air passage 54 in the first section 18, while
the suction chamber 48 is connected via a passage 56 in the first
section 18 with an internal suction passage 58 formed in the second
section 20. As shown in FIG. 3, the liquid inlet 40 is connected
through a liquid passage 60 with an axial bore 62 formed in the
first section 18 opposite the proximal end 14. A needle valve 64
having a thumbwheel 66 is provided across the liquid passage 60 to
control the flow rate of the irrigating liquid.
The swivel joint mechanism 22 includes an O-ring 68 received within
a pair of opposed annular grooves, one formed in the first section
18 and the other in the main piece 24 of the second section 20. The
O-ring 68 permits rotation of the main piece 24 with respect to the
first section 18 but serves to prevent the main piece 24 from
separating from the section 18. The swivel joint mechanism 22 also
includes a substantially cylindrical member 70, the externally
threaded end of which is firmly screwed into the main piece 24 and
the other end of which extends into a tubular extension 72 of the
first section 18 and is sealed therefrom by an O-ring 74. The
cylindrical member 70 has a central through-bore in which is
press-fitted an integral central pipe 76 which extends into the
axial bore 62 in the first section 18 and is sealed by an O-ring
78. Thus, a sealed annular space 80 is defined between the first
section 18 and the main piece 24, which space 80 is communicated by
the passage 56 (FIG. 1) with the suction chamber 48. The annular
space 80 is then connected with the internal suction passage 58 by
way of two or more axial passages 82 formed in the member 70. The
central pipe 76 has a through passage 84 which opens into the bore
62.
The passage 84 in the central pipe 76 is connected by a liquid
conduit 86 with a passage 88 formed in the head piece 30 and
opening into the smallest bore portion of a multistage stepped bore
90 in the head piece 30. An exchangeable adapter or suction tube
holder 92 with O-rings 94 and 96 is screwed into the stepped bore
90 at 98 to form sealed annular upper and lower spaces 100 and 102
between the bore 90 and the holder 92. The holder 92 firmly
supports a suction tube 104 made, for example, from stainless
steel, and extending outward through a nozzle 106 in the head piece
30. The upper annular space 100 is connected on one hand with the
suction passage 58 via a passage 108 in the head piece 30 and on
the other hand with the suction tube 104 by means of a diametrical
passage 110 and a longitudinal passage 112, both formed in the
holder 92.
An aspiration needle 114 is detachably mounted to the suction tube
104. The needle 114 may be made from a flexible transparent
material such as polyethylene (PE) and polypropylene (PP) and is
tapered toward its free end. The length of the aspiration needle
114 may generally vary from 15 to 25 mm. For the purposes of
irrigating a root canal of a tooth, it is desirable that the free
end of the needle 114 has an outer diameter of less than about 0.5
mm. However, the size of the needle 114 may be altered as required.
Further, the needle 114 may be made from a material such as
stainless steel, which is capable of withstanding inside vacuum
when the wall thickness of the needle is extremely reduced. In this
instance, the suction tube 104 and the aspiration needle 114 may be
formed as a one-piece element.
In use, an end of an exhaust hose 116 is connected to the venturi
tube 46 and the other end of the hose is led to a conventional
waste liquid disposal facility such as a spitoon (not shown)
normally provided in the dental unit. Then, a coupling joint 32 of
a multiple-channel hose is snap fitted to the irrigating instrument
10 as shown in FIG. 3. Commercially available dental units
fabricated by various manufacturers and purchased by dentists today
are generally provided with a multiple-channel hose for supplying
the compressed air and pressurized cooling and rinsing water to
turbine-driven dental tools. The supply of air through the air
channel is generally controlled by a foot pedal valve. The hose is
connected to the turbine tool by a coupling joint or hose
connector. Various types of coupling joints are currently used for
this purpose, an example is as shown in FIG. 3. This coupling joint
32 is of the quick or one-touch coupling type and includes a
slidable collar 118 for urging balls 120 radially inwardly into
engagement with an annular groove of the tool, such as the annular
groove 34, to perform coupling. The joint 32 has a central water
supply passage 122 communicating with the water channel of the hose
(not shown) and a parallel air supply passage 124 connected with
the air channel. The air passage 124 opens to the side of the core
36 located between O-rings 126 and 128. If the existing dental unit
is equipped with other types of coupling joints such as a
screw-thread joint or bayonet joint, it is possible to couple that
joint with the irrigating instrument 10 according to the present
invention by an adaptor provided with the joint coupler 32, as
illustrated.
When the water under pressure is fed from a remote water source in
the dental unit to the water inlet 40 of the handpiece, the water
flows into the passage 60 and its flow rate and the pressure are
controlled manually by regulating the valve 64. The water passes
the bore 62, pipe 76, liquid conduit 86, and passage 88 to flow
into the annular space 102 in the head piece 30. Then the water is
ejected through the nozzle 106 in the form of an annular water jet,
flowing along and around the suction tube 104 and the aspiration
needle 114. It is generally considered desirable to adjust the flow
control valve 64 in such a manner that, when the second section 20
of the handpiece 12 is turned to direct the aspiration needle 114
upward, the water jet is ejected to a sufficient height that will
carry it beyond the free end of the aspiration needle 114.
FIG. 4 schematically shows a manner in which the aspiration needle
114 is inserted into the root canal 130 of a tooth 132 and the
water jet flows along the needle 114 to wash away the cuttings and
pulp tissues in the root canal.
Simultaneously with the water supply, the foot pedal valve (not
shown) of the dental unit is operated to supply the compressed air
to the air inlet 38 of the handpiece 12. As the air is ejected from
the air nozzle 44 of the suction pump 42, a partial vacuum is
established within the vacuum chamber 48 and is transmitted through
the passage 56, annular space 80, axial passages 82, internal
suction passage 58, annular space 100, passage 110, passage 112,
and suction tube 104 to the aspiration needle 114, whereby the
rinsing water in the root canal 130 is sucked into the aspiration
needle 114, as shown in FIG. 5, together with the cuttings and the
tissue fragments and is discharged through the suction passages
toward the exhaust hose 116.
Where it is desirable to perform irrigation with irrigating
solutions such as peroxide solution in place of rinsing water, a
sealed container receiving such a solution may be provided and
pressurized by introducing the compressed air from the dental unit.
The pressurized irrigating solution may then be fed by a supply
conduit either to the liquid channel of the multiple-channel hose
or to the liquid passage 122 of the coupling joint 32.
It will be appreciated that, according to the present invention,
the irrigating solution is simultaneously extracted and evacuated
by the same irrigating instrument. This eliminates the need for
separate suction devices such as saliva removers and facilitates
the work of the dentists. The aspiration needle 114 may be inserted
at any desired depth of a root canal depending on the nature and
stage of the treatment, and the transparency of the needle 114
assists in the visual inspection of the irrigating operation. The
flexibility of the aspiration needle 114 enables the insertion of
the needle tip within a narrow root canal of any complex structure.
Thus, any portion in a root canal may be perfectly rinsed and the
cuttings or other materials adhering to the root canal wall are
clearly washed away. Particularly, those regions of the root canal,
such as the root canal apex and apical dental foramen, that are apt
to trap an air bubble and are difficult to be rinsed with the
conventional irrigating instrument, can be perfectly irrigated and
the irrigating solution after use may be readily removed from those
regions by suction.
The irrigated root canal may be dried by using the irrigating
instrument 10 of the present invention. To this end, the needle
valve 64 or a foot pedal valve (not shown) for controlling the
liquid supply is operated until the liquid supply is shut off. The
aspiration needle 114 is moved up and down along the root canal, to
discharge all droplets of irrigating solution adhering to the
internal wall of the root canal. On so doing, a flow of fresh air
is drafted into the root canal due to suction by the airjet pump
42. The draft of air accelerates the drying of the root canal, and
the root canal is now ready for a subsequent filling operation.
It will be also appreciated that the irrigating instrument 10
according to the present invention may be used interchangeably with
the dental turbine handpieces, because the suction pump 42 is
operable with the compressed air. Thus, the irrigating instrument
may be controlled by the conventional foot pedal valves provided in
the existing dental units. As most dentists are skilled in the
operation of foot-pedal controlled turbine handpieces, the
irrigating instrument 10 of the present invention may be controlled
without difficulty. This will enhance the efficiency of the
irrigation operation. Also, the flow rate of the compressed air may
be varied by regulating the foot pressure on the foot pedal, so as
to control the suction force prevailing at the aspiration needle
114.
FIG. 6 illustrates a modified embodiment of the present invention.
This embodiment differs from that shown in FIGS. 1 through 3 only
in the direction of the suction pump. Therefore, like reference
numerals are used to indicate equivalent parts and members and the
description thereof will not be repeated. In this embodiment, the
air nozzle 44' and the venturi tube 46' are bent rearward at a
right angle so that the exhaust port is directed parallel to the
longitudinal centerline of the handpiece 12. This arrangement will
permit the operator to grip the handpiece 12 more conveniently.
During irrigation using the irrigating instrument 10 according to
the present invention, it will happen that the narrow aspiration
needle 114 or suction tube 104 becomes clogged with solid materials
such as cuttings. In that event, it is desirable to backwash the
needle 114 or suction tube 104 by supplying the compressed air in
the reverse direction to remove the clogging materials.
FIGS. 7 through 9 illustrate a third embodiment of the present
invention which permits the above-mentioned backwashing. Parts and
members equivalent to those of the preceding embodiments are
designated by like reference numerals and their explanations are
omitted. Only the different parts and members will be described
hereinafter.
In this embodiment, the venturi tube 200 of the airjet type suction
pump 202 is bent, as in the second embodiment shown in FIG. 6. As
will be best understood from FIG. 8, the suction pump 202 is
provided with an integral built-in valve mechanism designated
generally by reference numeral 204. The valve mechanism 204
includes a valve cylinder 206 which forms an integral horizontal
extension of the venturi tube 200. A stationary sleeve 208 having
ports 210 is received within the valve cylinder 206 and is fixed in
position by a lock screw 212. The ports 210 of the sleeve 208 are
connected by a passage 214 with an air supply conduit 216 (FIG. 7)
which is communicated with the air inlet 38.
A hollow movable spool 218 is slidably mounted within the fixed
sleeve 208. This spool 218 is made as a one-piece member with the
air nozzle 220 of the suction pump 202. The compressed air from the
ports 210 is admitted into an annular space 222 around the movable
spool 218 and then introduced through ports 224 into the ejection
port 226 of the air nozzle 220. The movable spool 218 is urged to
the left by a coil spring 228, but its leftward movement is limited
by a circlip 230 mounted to the spool 218 and abutting against the
stationary sleeve 208. An end cap 232 is slidably received within
the valve cylinder 206 and is rigidly connected with the movable
spool 218 by a suitable fastening means such as a screw thread or
interference fit. A closure plunger 234 having an integral push rod
236 is mounted within the movable spool 218 and is biased toward
the left by a coil spring 238. Designated at 240 through 248 are
O-rings for sealing purposes. Liquid supply passages are formed in
the same manner as in the first embodiment shown in FIG. 3. As is
apparent from FIG. 7, the suction chamber 48 of the vacuum pump 202
is connected by passages 250 and 252 with the annular space 80.
The operation of the third embodiment provided with a backflow
valve mechanism is as follows.
As each member of the valve mechanism is in the position shown in
FIGS. 7 and 8, the compressed air flows as shown by arrows, and
induces partial vacuum in the vacuum chamber 48 thereby causing a
suction force at the aspiration needle 114.
When the aspiration needle 114 or suction tube 104 is clogged or
jammed for any reason, the operator presses the push rod 236
together with the end cap 232 as shown in FIG. 9. This causes the
movable spool 218 and the closure plunger 234 to move the right,
whereby the annular space 222 is brought into open communication
with the vacuum chamber 48 thereby releasing the compressed air
toward the suction passages. At the same time, the ports 224 of the
air nozzle 220 is closed by the plunger 234 and the exhaust port 52
is shut off by the frontal end of the nozzle 220. Thus, the
compressed air within the chamber 48 is forced to flow into the
suction passages in the reverse direction, as shown by arrows, and
forced out from the suction tube 104 and aspiration needle 114,
thereby blowing out the clogging materials. When the clogged
materials are removed by repeating several backflow operations, the
operator is then able to continue the irrigating operation.
While the present invention has been described with reference to
the specific embodiments thereof, it should be understood that it
is not limited thereby and various changes and modifications may be
made therein within the scope of the appended claims.
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